Different state has different corporate law

You did not say which state you are suing and which state the company or corporation is registered under. It is hard to answer.

For example, in Virginia, State Corporation Commission (SCC) manages company registration, and serves as statutory agent of service of process. Find the simliar organization in your state government, and READ, READ, READ CAAREFULLY what they say about service of process.

Here is the example for Virginia SCC.
https://www.scc.virginia.gov/clk/svcproc.aspx